Which country did my sister visit?

My sister is always talking about pilots. And her passengers. And planes in general. She’s a flight attendant, see, and she is OBSESSED with all things aeronautical (always has been). On the rare occasions that she’s back in the country long enough to come round for dinner, conversation invariably turns to her travels and I have to feign interest, when all I really want to do is crawl under the table and go to sleep.

Yesterday was one of those occasions. In an attempt at being a supportive sibling I took a deep breath and inquired about how her job was going, asking her where she’d gone on her latest trip.

To my surprise, my sister passed me an envelope. "Thank you for asking," she said, with a smile. "I do realise it takes a great deal of effort to cope with all my chatter – ah, I’ll start waffling if I’m not careful. In short, I appreciate the attempt, brother. And so here’s a little gift for you – I know you like puzzles…" – my eyes lit up – "…If you can solve this, you’ll find out where I went on my last trip. And I promise I shan’t talk about work any more this dinnertime."

She’d made me a puzzle! And as for conversation she was true to her word! I put the envelope to one side, unopened, for the duration of our meal and we had a really lovely evening together, just like old times. As soon as she’d gone I tore into it eagerly and soon cracked the puzzle (naturally), but here’s the question – can you? There were just two items inside the envelope:

1. A seating diagram headed "My designated section on the flight"

_{Click image to enlarge detail (extraneous content removed). Text version of seating plan available in source.}

2. A handwritten note, which read…

This particular flight was genuinely lovely – I got to know all of my passengers really well. I even remembered to take their in-flight meal orders at the right point of the journey (not always a given)! We flew through the airspace of five different countries (each of which shared the same specific connection with the country of my final destination), and just before we landed I even got time to practise a little of my Spanish (even though they don’t speak it there).

Of course, the details of her puzzle were fictitious (you’d have a hard job flying through just the five countries she was referring to, for one thing!). But it all fell into place in the end, with everything pointing towards one particular country.

Which was it?

TASK: Solve my sister’s puzzle to identify the country to which she most recently travelled. Show me your working!